Ultralight aircraft

Abstract

Improved ultralight aircraft constructed with a tubular keel extending over the length of the aircraft from forward of its wing to the tail thereof. The aircraft includes a cantilever engine mount which is carried on a pair of mounting plates extending longitudinally from the forward end of the tubular keel. The propeller shaft, driven by the engine through a speed reduction arrangement, is supported in a bearing disposed on the engine mount. The aircraft includes a cage assembly for the operator's seat and has upright tubular rails and a pair of longitudinally extending side rails mounted on a shock absorbing landing gear. The landing gear has a nose wheel and a pair of laterally spaced rear wheels. The rear wheels are carried on the outer ends of a pair of longitudinally spaced, transversely extending tubular members. The forward of the tubular members is journaled for rotation on the underside of said side rails, and the rear member is releasably urged against the upper surface of the side rails by elastic bands or cords, which enable the rear member to move vertically relative to said side rails in response to landing impact. The aircraft is further constructed with full length ailerons, which are pivotably supported on the trailing edges on said wing. Each aileron is formed of a tubular frame disposed within a tapered fabric sheath which is in tension because of its tapered configuration and its dimensional relationship to the frame. The frame includes outer peripheral tubular portions and a plurality of parallel, laterally spaced cross tubes, each affixed at its outer end to the peripheral portion of the frame.

Having thus disclosed this invention, what is claimed is: 
     
       1. In an ultralight aircraft of the type having a unitary tubular keel, a wing mounted on the upper surface of said keel with its leading edge adjacent the outer front end of said keel, and an internal combustion engine and a propeller to be driven thereby, an improved cantilever mounting frame for supporting said engine and said propeller on said keel, said mounting frame comprising a pair of laterally spaced plates disposed along opposite exterior side surfaces of the keel and longitudinally extending forwardly of the front end of said keel, first reinforcing block members disposed between said plates and said side surfaces of said keel, said first block members having flat outwardly facing surfaces in mated surface-to-surface engagement with said plates and inwardly-facing concave surfaces in mated surface-to-surface engagement with said exterior side surfaces of said keel, second reinforcing block members disposed inwardly of said keel adjacent said first block members, said second block members having outwardly-facing convex surfaces in mated surface-to-surface engagement with opposite interior side surfaces of said keel, said first and second block members being formed of a relatively rigid, slightly compressible synthetic plastic material, said plates, said first and second block members and said keel having plural registered mounting holes, plural fasteners extending through said mounting holes to secure said plates, said first and second block members, and said keel together with said first and second block members. compressed against said exterior and interior surfaces of said keel to prevent stressing thereof, a bracket on which said engine and propeller are supported, and resilient shock absorbing fasteners affixing said bracket between the forwardly extending ends of said mounting plates for dampening vibration of said engine, whereby said cantilever mounting frame substantially isolates engine vibrations from said keel. 
     
     
       2. The improved cantilever mounting frame in an ultralight aircraft as set forth in claim 1, and characterized further in that the major cross sectional dimensions of said plates are disposed vertically and said bracket is disposed horizontally therebetween, said propeller including a drive shaft and a bearing therefor drivingly coupled to the engine shaft by a speed reduction transmission means, the engine being mounted on the upper surface of said bracket and said bearing for said propeller shaft mounted on the undersurface of said bracket. 
     
     
       3. In an ultralight aircraft of the type having a wing with a leading and trailing edge and an aileron pivotably mounted along the trailing edge on each side of said wing, an improved structure of each said aileron characterized by its ease and quickness of assembly, each said aileron comprising a tubular aluminum frame of tapered configuration from end-to-end, said frame including a leading edge tube and a trailing edge tube, and laterally extending, spaced cross tubes fastened to and extending between the trailing and leading edge tubes of said frame, and a fabric sheath having one open end through which said frame is received telescopically by said sheath, said sheath being tapered and dimensioned relative to said frame to snugly fit in an automatically tensioned manner about said frame with sufficient tautness in said sheath that doping or shrinking thereof is not required, said sheath including a closure flap at one side of said open end and extending longitudinally outwardly of said sheath for reverse folding to the opposite side of said open end to close it about said frame, said closure flap and said opposite side of said open end having cooperating means for affixation thereof to provide a smooth closure of said open end. 
     
     
       4. The improved aileron structure in an ultralight aircraft as set forth in claim 3 and characterized further in that the cross tubes thereof are fitted at each end thereof through holes in opposed inner wall portions of the leading edge tube and the trailing edge tube, each of said cross tubes being affixed therein by fasteners extending through openings in the outer wall portions of said leading and trailing edge tubes registered with said holes, said fasteners extending into the outer ends of each cross tube for fastening the same in assembled relation within the aileron frame. 
     
     
       5. The improved aileron structure in an ultralight aircraft as set forth in claim 4 and characterized further in that each of said fasteners is a rivet having a head on its outer end only. 
     
     
       6. In an ultralight aircraft of the type having a tubular keel and a cage assembly depending from the underside of said keel, an improved shock-absorbing landing gear assembly for said cage assembly, said landing gear assembly comprising side rails affixed to said cage assembly to extend longitudinally of said keel, a pair of landing gear tubes laterally extending and longitudinally spaced relative to said side rails, the forward one of said landing gear tubes being disposed on the underside of said side rails and the rearward one of said landing gear tubes being disposed above said side rails, a pair of landing wheels rotatably mounted on the laterally outward ends of said landing gear tubes for ground engagement and rotation about a lateral axis of the aircraft, journal means affixed to the underside of said side rails and rotatably clamping said forward landing gear tube, and spring means extending between said side rails and said rearward landing gear tube for urging it into a normal position resting in juxtaposition on the upper surfaces of said side rails and for permitting yielding displacement of said rearward landing gear tube upwardly upon ground impact of said wheels during landing of the aircraft for absorbing the shock of such impact, said forward landing gear tube being operative to rotate in said journal means upon such impact to constrain said rearward landing gear tube to move yieldably in a generally arcuate path for stabilizing and modulating the yielding displacement of said rearward landing gear tube. 
     
     
       7. The improved landing gear assembly in an ultralight aircraft as set forth in claim 6 and characterized further in that said journals are mounting blocks for the forward landing gear tube and include a vibration dampening material, and in which said spring means comprises elastic cords disposed about the rear landing gear tube at the locations where it traverses said side rails to urge said tube toward said juxtaposition with the side rails, said landing gear tubes and rear wheels carried thereby being pivotable together about said lateral axis for absorbing ground shock. 
     
     
       8. The improved landing gear assembly in an ultralight aircraft as set forth in claim 6 and characterized further in that said elastic cords comprise bungee cords, each being looped over the rear landing gear tube a number of times and in which said mounting blocks on the forward landing gear tube include an upper block of rubber having a semi-cylindrical recess and a lower block of rigid synthetic plastic material also having a semi-cylindrical recess therein, said rubber and plastic blocks serving as dampening cylindrical journals for the forward landing gear tube, whereby ground impact upon the rear wheels of said landing gear causes angular movement of both the forward and rear landing gear tubes, said movement being releasably restrained by both the cylindrical journals and by said bungee cords.